Milk Docosahexaenoic Acid Content Research Articles

Tissue Accretion and Milk Content of Docosahexaenoic Acid in Female Rats after Supplementation with Different Docosahexaenoic Acid Sources

Background: Docosahexaenoic acid (DHA) is highly concentrated in the mammalian nervous and visual system. The fatty acid, which is required by the fetus and the newborn, is supplied by the mother from their tissue reservoirs. It has been suggested that mother’s supplementation with DHA during pregnancy and even before pregnancy. Different sources of DHA are available for supplementation such as: single-cell algae triglycerides (TG), egg’s yolk phospholipids (PL), DHA ethyl esther (EE), and sn-2 DHA monoacylglyceride (MG). We evaluated comparatively the effectiveness of these different DHA sources to produce tissue DHA accretion and to increase milk DHA content. Methods: Female Wistar rats fed a diet which provided no DHA, were daily supplemented by 40 days before mating (BM) and during the pregnancy with either TG, PL, EE, or MG to an amount which provided 8 mg/kg b.w. of DHA. Samples of blood plasma, erythrocytes, hepatic and adipose tissue were obtained from rats at the BM condition and after the delivery (AD), and milk samples were also obtained from the gastric content of the pups nursed by the rats at day 3, 11 and 20 of suckling. Samples were processed to assess DHA and arachidonic acid (AA) content by gas-chromatography. Results: TG, PL, EE, and MG supplementation produced a similar intestinal absorption of DHA as estimated from the plasma DHA at the BM condition. However, PL and MG supplementation produced a higher accretion of DHA into erythrocytes, hepatic, and adipose tissue than TG and EE supplementation at the BM condition. AA content was not modified by the different supplementing oils. A reduction of the DHA content of plasma, erythrocytes, hepatic and adipose tissue at the AD condition was observed, and a reduction of AA for the hepatic and adipose tissues was also observed, suggesting the importance of these tissues as DHA and AA reservoirs. Milk secretion from PL and MG supplemented rats showed a higher DHA content than secretion from TG- and EE-supplemented rats. Conclusions: We conclude that PL and MG supplementation provides higher tissue DHA accretion and higher milk DHA content than TG and EE supplementation. However, we were not able to visualize the comparative advantages derived from PL vs. MG supplementation.

Polyunsaturated fatty acids in human milk: an essential role in infant development.

The n-6 and n-3 fatty acids are essential dietary nutrients required for optimal growth and development, particularly of the brain and retina. Large amounts of the n-3 fatty acid docosahexaenoic acid (DHA) is accumulated in the brain grey matter and the visual elements of the retina during development, and reduced DHA in these tissues can result in decreased visual and psychomotor development. Although the possible importance of differences in n-6 and n-3 fatty acids, particularly DHA, between human milk and infant formulas has been the subject of intense clinical research, the variability in the essential fatty acid content of milk within and among different populations of women and implications of this to infant growth and development have received much less attention. Considerable research has shown that the DHA content of the maternal diet is the most important determinant of the amount of DHA secreted in milk, and thus the dietary intake of the breastfed infant. The DHA content of human milk varies over 10-fold, being lowest in women with no intake of DHA and highest in women with high intakes of DHA, which is found predominantly in fatty fish. The requirement for n-3 fatty acids, and the balance of n-6 and n-3 fatty acids for optimal growth and development of the brain and retina, and long-term minimization of risk of chronic disease remains as one of the most important questions in infant nutrition. Dietary recommendations to modifying dietary fat with the aim of reducing risk of chronic disease, including obesity and cardiovascular disease in adults, need to consider that when followed by pregnant women, these recommendations can have a marked effect on the amount and balance of n-6 and n-3 fatty acids secreted in milk.

Effect of Combinations of Fish Meal and Feather Meal on Milk Fatty Acid Content and Nitrogen Utilization in Dairy Cows

The effect of supplemental fishmeal in combination with feathermeal at two different proportions in the diet on milk docosahexaenoic acid (DHA) content was investigated. Recently, benefits to human health have been attributed to the consumption of this fatty acid, which is normally present in marine lipids. Six Holstein cows past peak lactation were used in a Latin square design with a 2×3 factorial arrangement of treatments. Fish- and feathermeals were prepared as pellets at 4:1 and 1:4 combinations and offered at 3.75, 11.75, and 27% of the diet. The supplements were top-dressed onto a basal diet based on corn silage that was progressively replaced by supplement. Nitrogen balance measures were made during the experiment because of the wide range in crude protein content of experimental diets. Milk protein content increased with level of supplementation in the diet reflecting the protein quality of the supplements used. There was overall higher milk DHA content when cows consumed the supplement containing more fishmeal than feather meal. Milk DHA content increased in a quadratic fashion, as more of either supplement was included in the diet. Apparent transfer efficiency of DHA from diet to milk declined with increasing amount of DHA in the diet. Results from this experiment suggest that transfer of docosahexaenoic acid from diet to milk may depend on diet composition and quantity present in the diet.

Dietary strategies for increasing docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations in bovine milk: a review.

Abstract A review was made of the literature concerning the metabolism of fatty acids in the dairy cow, and the potential of increasing the content of the essential fatty acids eicosapentaenoic acid (EPA; C20:5) and docosahexaenoic acid (DHA; C22:6) in cows' milk. EPA and DHA are two n-3 polyunsaturated fatty acids, which can be synthesised from a-linolenic acid (LNA, C18:3). Both EPA and DHA have anti-thrombotic and anti-carcinogenic effects. The UK Department of Health has recommended that the daily human intake of total n-3 PUFA should be 0.2 g/d, which is approximately double the current average intake. The richest source of dietary EPA and DHA is marine products, but the consumption of fish in the UK is declining. Milk fat consumption constitutes 30% of total fat consumption in the UK diet, and so enhancing the concentration of EPA and DHA in milk fat could be an effective means of increasing the consumption of these fatty acids in the UK. Grass and linseed are rich sources of LNA for dairy cows, while fish oil or marine algae are the richest sources of EPA and DHA. However, a large proportion of these fatty acids ( ca 0.9) are hydrogenated to more saturated fatty acids by the microorganisms in the rumen. The proportion of absorbed n-3 PUFA is therefore only about 7 g/kg ingested n-3 PUFA. Absorbed EPA and DHA are transported around the body as phospholipids, associated with the high-density lipoprotein fraction of the plasma. This fraction is not a good substrate for lipoprotein lipase, which is the enzyme in the mammary gland that removes fatty acids from the circulation for incorporation into milk fat. The uptake by the mammary gland of absorbed EPA and DHA is therefore extremely low. The concentration of EPA and DHA in milk fat therefore remains low even when the diet is enriched with these fatty acids. It is possible that the EPA and DHA present in the milk arise from de novo synthesis of these acids from LNA in the mammary gland. However, while EPA is synthesised from LNA, there appears to be a block on the subsequent synthesis of DHA from EPA. EPA and DHA are not stored in adipose tissue triacylglycerols, and they are not used for oxidative metabolism. There is therefore little competition for circulating EPA and DHA between the mammary gland and adipose tissue, or between secretion and oxidation. There is some potential storage of these acids in the phospholipids of muscle tissue and adipose tissue. Grass is a rich source of LNA, and the LNA content of milk can be enhanced by increasing the herbage content of the diet. This potentially provides more precursors of EPA and DHA. However, increasing the proportion of forage in the diet also tends to increase the extent of rumen biohydrogenation of PUFA as this process is encouraged by higher rumen pH and reduced propionate production. Including either fish oil or some species of marine microalgae in the diet increases the EPA and DHA content of milk. However, these oils can adversely affect rumen function, so that total dry matter intake and milk fat content are reduced. Feeding fish oils to ruminant animals may also not be a sustainable practice in the longer-term. Protecting marine oils from rumen biohydrogenation should prevent the adverse effects on rumen function. However, the evaluation of a protected marine microalgae product suggested that the protection was far from complete, and a reliable means of treating algae to protect it from rumen metabolism still awaits development. Further enhancement of the EPA and DHA content of cows' milk requires more research. Issues, which need to be addressed, are the development of a suitable oil supplement, and a reliable means of protecting it from rumen biohydrogenation. A means of transporting the absorbed EPA and DHA in the circulation so that it is readily taken up by the mammary gland for incorporation into the milk fat also needs to be developed. Changes in the marketing of milk that has been improved in this way would also be required to meet the increased cost of producing this nutritionally enhanced milk.

Dietary strategies for increasing docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) concentrations in bovine milk: a review.

Abstract A review was made of the literature concerning the metabolism of fatty acids in the dairy cow, and the potential of increasing the content of the essential fatty acids eicosapentaenoic acid (EPA; C20:5) and docosahexaenoic acid (DHA; C22:6) in cows' milk. EPA and DHA are two n-3 polyunsaturated fatty acids, which can be synthesised from a-linolenic acid (LNA, C18:3). Both EPA and DHA have anti-thrombotic and anti-carcinogenic effects. The UK Department of Health has recommended that the daily human intake of total n-3 PUFA should be 0.2 g/d, which is approximately double the current average intake. The richest source of dietary EPA and DHA is marine products, but the consumption of fish in the UK is declining. Milk fat consumption constitutes 30% of total fat consumption in the UK diet, and so enhancing the concentration of EPA and DHA in milk fat could be an effective means of increasing the consumption of these fatty acids in the UK. Grass and linseed are rich sources of LNA for dairy cows, while fish oil or marine algae are the richest sources of EPA and DHA. However, a large proportion of these fatty acids ( ca 0.9) are hydrogenated to more saturated fatty acids by the microorganisms in the rumen. The proportion of absorbed n-3 PUFA is therefore only about 7 g/kg ingested n-3 PUFA. Absorbed EPA and DHA are transported around the body as phospholipids, associated with the high-density lipoprotein fraction of the plasma. This fraction is not a good substrate for lipoprotein lipase, which is the enzyme in the mammary gland that removes fatty acids from the circulation for incorporation into milk fat. The uptake by the mammary gland of absorbed EPA and DHA is therefore extremely low. The concentration of EPA and DHA in milk fat therefore remains low even when the diet is enriched with these fatty acids. It is possible that the EPA and DHA present in the milk arise from de novo synthesis of these acids from LNA in the mammary gland. However, while EPA is synthesised from LNA, there appears to be a block on the subsequent synthesis of DHA from EPA. EPA and DHA are not stored in adipose tissue triacylglycerols, and they are not used for oxidative metabolism. There is therefore little competition for circulating EPA and DHA between the mammary gland and adipose tissue, or between secretion and oxidation. There is some potential storage of these acids in the phospholipids of muscle tissue and adipose tissue. Grass is a rich source of LNA, and the LNA content of milk can be enhanced by increasing the herbage content of the diet. This potentially provides more precursors of EPA and DHA. However, increasing the proportion of forage in the diet also tends to increase the extent of rumen biohydrogenation of PUFA as this process is encouraged by higher rumen pH and reduced propionate production. Including either fish oil or some species of marine microalgae in the diet increases the EPA and DHA content of milk. However, these oils can adversely affect rumen function, so that total dry matter intake and milk fat content are reduced. Feeding fish oils to ruminant animals may also not be a sustainable practice in the longer-term. Protecting marine oils from rumen biohydrogenation should prevent the adverse effects on rumen function. However, the evaluation of a protected marine microalgae product suggested that the protection was far from complete, and a reliable means of treating algae to protect it from rumen metabolism still awaits development. Further enhancement of the EPA and DHA content of cows' milk requires more research. Issues, which need to be addressed, are the development of a suitable oil supplement, and a reliable means of protecting it from rumen biohydrogenation. A means of transporting the absorbed EPA and DHA in the circulation so that it is readily taken up by the mammary gland for incorporation into the milk fat also needs to be developed. Changes in the marketing of milk that has been improved in this way would also be required to meet the increased cost of producing this nutritionally enhanced milk.

Efecto de la suplementación de la dieta de la madre durante la lactancia con ácidos grasos omega 3 en la composición de los lípidos de la leche

Introduction : Docosahexaenoic acid (DHA) is an important component of membrane phospholipids in brain and retinal tissues. The capability of infants to form DHA may be inadequate to support their metabolic requirements. Indeed they are dependent on the maternal supply. Women with a customarily high consumption of marine foods show increased levels of DHA in their breast milk. In Chile there is a low consumption of marine foods. Objective : To determine whether DHA supplementation of lactating women with jurel increases the DHA content of breast milk. Breast feeding women were randomly assigned to a supplemented or control group. The supplemented group (n = 12) consumed 160 g of jurel twice a week for 2 weeks, the control group (n = 12) maintained their usual diet. The jurel ( Trachurus murphyi ) contained 621mg of DHA per 100 g edible portion. Results : DHA supplementation increased DHA intake from 64 mg per day to 335.9 mg/day. Basal line DHA levels in milk were 0.15 ± 0.05% of total fatty acids and increased significantly to 0.22 ± 0.10% (p < 0.05). There was no effect of dietary DHA on breast milk arachidonic acid levels. Conclusion : maternal DHA supplementation with jurel significantly elevated milk DHA content.

Docosahexaenoic acid transfer into human milk after dietary supplementation: a randomized clinical trial

Docosahexaenoic acid (DHA) is important for infant development. The DHA transfer from maternal diet into human milk has not been investigated in detail. We studied the effects of DHA supplementation on the fatty acid composition of human milk and the secretion of dietary (13)C-labeled fatty acids, including DHA, into human milk. Ten lactating women were randomized to consume, from 4 to 6 weeks postpartum, an oil rich in DHA (DHASCO, 200 mg of DHA/day) (n = 5) or a placebo oil (n = 5). Dietary intakes were followed by 7-day protocols. On study day 14 a single dose of [U-(13)C]DHASCO was given orally, milk samples were collected over 48 h, and milk production was recorded. Milk fatty acid composition was determined by gas-liquid chromatography and isotopic enrichment was determined by gas chromatography- combustion-isotope ratio mass spectrometry (GC-C-IRMS). Milk DHA content did not differ between the supplemented and placebo group at study entry (0.29 vs. 0.28 wt%, median). After 2 weeks of supplementation the milk DHA content was almost 2-fold higher in the supplemented versus placebo group (0.37 vs. 0.21 wt%, P = 0.003). Cumulative recovery of [(13)C]palmitic, [(13)C]oleic, and [(13)C]docosahexaenoic acids in human milk at 48 h was similar between supplemented and placebo groups (palmitic acid 7.40 vs. 8. 14%, oleic acid 9.14 vs. 9.97%, and docosahexaenoic acid 9.09 vs. 8. 03% of dose, respectively). Notable lower recovery was observed for [(13)C]myristic acid in both the supplemented and placebo groups, 0. 62 versus 0.77% of dose. Dietary DHA supplementation increases the DHA content in human milk. DHA transfer from the diet into human milk is comparable to palmitic and oleic acid transfer.

Introduction

: Measure concentrations of the neurogenic, pro-neurogenic, pro-synaptogenic and anti-inflammatory mediator N-docosahexaenoylethanolamine (synaptamide) in relation to its precursor docosahexaenoic acid (DHA) in breast milk.: Postpartum women were recruited prior to discharge. We supplemented half the subjects with omega-3 fatty acids. Breast milk samples were collected at 1, 4 and 8 weeks. Synaptamide and DHA concentrations were determined by liquidchromatography/tandem mass spectrometry (LC-MS/MS) and gas chromatography, respectively.: Synaptamide was detected in all breast milk samples. The concentration ranged from 44 to 257 fmol/mL. Omega-3 fatty acid supplementation did not affect DHA or synaptamide concentration in breast milk due to a high-DHA-containing diet self-selected by control mothers. Nevertheless, synaptamide levels significantly correlated with DHA concentration in breast milk (r = 0.624, P < 0.001).: This is the first demonstration of detectable concentrations of synaptamide in human breast milk. Although the attempt to raise the milk DHA content by omega-3 fatty acid supplementation was not successful in the current study, the positive correlation observed between synaptamide and DHA concentration suggests that synaptamide levels in human milk can be raised by proper omega-3 fatty acid supplementation that is known to increase DHA.

Author index

: Measure concentrations of the neurogenic, pro-neurogenic, pro-synaptogenic and anti-inflammatory mediator N-docosahexaenoylethanolamine (synaptamide) in relation to its precursor docosahexaenoic acid (DHA) in breast milk.: Postpartum women were recruited prior to discharge. We supplemented half the subjects with omega-3 fatty acids. Breast milk samples were collected at 1, 4 and 8 weeks. Synaptamide and DHA concentrations were determined by liquidchromatography/tandem mass spectrometry (LC-MS/MS) and gas chromatography, respectively.: Synaptamide was detected in all breast milk samples. The concentration ranged from 44 to 257 fmol/mL. Omega-3 fatty acid supplementation did not affect DHA or synaptamide concentration in breast milk due to a high-DHA-containing diet self-selected by control mothers. Nevertheless, synaptamide levels significantly correlated with DHA concentration in breast milk (r = 0.624, P < 0.001).: This is the first demonstration of detectable concentrations of synaptamide in human breast milk. Although the attempt to raise the milk DHA content by omega-3 fatty acid supplementation was not successful in the current study, the positive correlation observed between synaptamide and DHA concentration suggests that synaptamide levels in human milk can be raised by proper omega-3 fatty acid supplementation that is known to increase DHA.